Multilayer golf ball

ABSTRACT

Multilayer golf balls comprising a thermoplastic or thermoset cover disposed about four or more thermoplastic layers are disclosed.

FIELD OF THE INVENTION

The present invention generally relates to multilayer golf balls, and more particularly to golf balls comprising a single or multilayer thermoplastic core, three or more thermoplastic intermediate layers disposed about the core, and a cover disposed about the intermediate layers.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 6,056,842 to Dalton et al. discloses a method of forming a golf ball by forming a core center, forming a laminate of core material, forming the laminate around the core center to form a core and forming a cover around the core.

U.S. Pat. No. 7,652,086 to Sullivan et al. discloses a golf ball comprising a center comprising a highly-neutralized thermoplastic copolymer of ethylene and an a,(3-unsaturated carboxylic acid, the acid being 100% neutralized by a salt of an organic acid, a cation source, or a suitable base of the organic acid; a cover; and an intermediate layer disposed between the center and the cover; wherein the golf ball has a first coefficient of restitution of 0.81 or greater when measured at an incoming velocity of 125 ft/s; and a sphere resulting from a combination of the center and the intermediate layer has a compression of 60 or greater.

U.S. Pat. No. 7,722,482 to Sullivan et al. discloses golf balls consisting of a multi-layer core and a cover. The multi-layer core consists of a center and an outer core layer that are both soft relative to a hard intermediate core layer. The outer core layer is thin relative to the center and the outer core layer.

U.S. Pat. No. 7,753,810 to Sullivan et al. discloses golf balls consisting of a multi-layer core and a cover. The multi-layer core consists of a small, hard center enclosed by a soft intermediate core layer and an outer core layer.

U.S. Pat. No. 8,123,631 to Sullivan et al. discloses golf balls consisting of a multi-layer core and a cover. The multi-layer core consists of a large center and a thin outer core layer that are both soft relative to a hard, thin intermediate core layer.

SUMMARY OF THE INVENTION

In a particular embodiment, the present invention is directed to a golf ball comprising a thermoplastic core, a first thermoplastic intermediate layer, a second thermoplastic intermediate layer, a third thermoplastic intermediate layer, and a cover. The core has a diameter of from 0.900 inches to 1.550 inches and a compression of 90 or less. The first and third thermoplastic intermediate layers each have a thickness of from 0.010 inches to 0.070 inches and a material hardness of from 60 Shore D to 80 Shore D. The second thermoplastic intermediate layer has a thickness of from 0.025 inches to 0.125 inches and a material hardness of 65 Shore D or less. The material hardness of the second thermoplastic intermediate layer is less than the material hardness of the first and third thermoplastic intermediate layers.

In another particular embodiment, the present invention is directed to a golf ball comprising a thermoplastic core, a first thermoplastic intermediate layer, a second thermoplastic intermediate layer, a third thermoplastic intermediate layer, and a cover. The core has a diameter of from 0.900 inches to 1.550 inches and a compression of 90 or less. The first thermoplastic intermediate layer has a thickness of from 0.025 inches to 0.125 inches and a material hardness of 65 Shore D or less. The second and third thermoplastic intermediate layers each have a thickness of from 0.010 inches to 0.070 inches and a material hardness of from 60 Shore D to 80 Shore D. The material hardness of the third thermoplastic intermediate layer is greater than the material hardness of the second thermoplastic intermediate layer, and the material hardness of the second thermoplastic intermediate layer is greater than the material hardness of the first thermoplastic intermediate layer.

DETAILED DESCRIPTION

The present invention is directed to a golf ball comprising a thermoplastic core encased in three or more thermoplastic intermediate layers, and a cover disposed about the encased core. The core is a single or multilayer core formed from one or more layers of the same or different thermoplastic materials. The intermediate layers include a relatively soft and thick thermoplastic layer and two relatively stiff and thin thermoplastic layers. The cover is a single or multilayer cover, each cover layer being formed from a thermoplastic or thermoset material.

Compositions

Suitable compositions for forming the thermoplastic core, intermediate, and cover layers include, but are not limited to, partially- and fully-neutralized ionomers, graft copolymers of ionomer and polyamide, and the following non-ionomeric polymers, including homopolymers and copolymers thereof, as well as their derivatives that are compatibilized with at least one grafted or copolymerized functional group, such as maleic anhydride, amine, epoxy, isocyanate, hydroxyl, sulfonate, phosphonate, and the like:

(a) polyesters, particularly those modified with a compatibilizing group such as sulfonate or phosphonate, including modified poly(ethylene terephthalate), modified poly(butylene terephthalate), modified poly(propylene terephthalate), modified poly(trimethylene terephthalate), modified poly(ethylene naphthenate), and those disclosed in U.S. Pat. Nos. 6,353,050, 6,274,298, and 6,001,930, the entire disclosures of which are hereby incorporated herein by reference, and blends of two or more thereof;

-   -   (b) polyamides, polyamide-ethers, and polyamide-esters, and         those disclosed in U.S. Pat. Nos. 6,187,864, 6,001,930, and         5,981,654, the entire disclosures of which are hereby         incorporated herein by reference, and blends of two or more         thereof;     -   (c) polyurethanes, polyureas, polyurethane-polyurea hybrids, and         blends of two or more thereof;     -   (d) fluoropolymers, such as those disclosed in U.S. Pat. Nos.         5,691,066, 6,747,110 and 7,009,002, the entire disclosures of         which are hereby incorporated herein by reference, and blends of         two or more thereof;     -   (e) non-ionomeric acid polymers, such as O/X- and O/X/Y-type         copolymers, wherein O is an olefin (e.g., ethylene), X is a         carboxylic acid such as acrylic, methacrylic, crotonic, maleic,         fumaric, or itaconic acid, and Y is a softening comonomer such         as vinyl esters of aliphatic carboxylic acids wherein the acid         has from 2 to 10 carbons, alkyl ethers wherein the alkyl group         has from 1 to 10 carbons, and alkyl alkylacrylates such as alkyl         methacrylates wherein the alkyl group has from 1 to 10 carbons;         and blends of two or more thereof, such as those disclosed in         U.S. Pat. No. 6,872,774, the entire disclosure of which is         hereby incorporated herein by reference;     -   (f) metallocene-catalyzed polymers, such as those disclosed in         U.S. Pat Nos. 6,274,669, 5,919,862, 5,981,654, and 5,703,166,         the entire disclosures of which are hereby incorporated herein         by reference, and blends of two or more thereof;     -   (g) polystyrenes, such as poly(styrene-co-maleic anhydride),         acrylonitrile-butadiene-styrene, poly(styrene sulfonate),         polyethylene styrene, and blends of two or more thereof;     -   (h) polypropylenes and polyethylenes, and blends of two or more         thereof;     -   (i) polyvinyl chlorides, and blends of two or more thereof;     -   (j) polyvinyl acetates, preferably having less than about 9% of         vinyl acetate by weight, and blends of two or more thereof;     -   (k) polycarbonates, blends of         polycarbonate/acrylonitrile-butadiene-styrene, blends of         polycarbonate/polyurethane, blends of polycarbonate/polyester,         and blends of two or more thereof;     -   (l) polyvinyl alcohols, and blends of two or more thereof;     -   (m) polyethers, such as polyarylene ethers, polyphenylene         oxides, block copolymers of alkenyl aromatics with vinyl         aromatics and poly(amic ester)s, and blends of two or more         thereof;     -   (n) polyimides, polyetherketones, polyamideimides, and blends of         two or more thereof;     -   (o) polycarbonate/polyester copolymers and blends of two or more         thereof; and     -   (p) combinations of any two or more of the above thermoplastic         polymers.

In a particular embodiment, each of the thermoplastic layers is formed from an ionomer composition. In a particular aspect of this embodiment, the ionomer composition optionally comprises one or more non-ionomeric polymers, wherein the total amount of non-ionomeric polymer(s) is less than 50 wt %, based on the total polymeric weight of the composition, and wherein the non-ionomeric polymer(s) are selected from the non-ionomeric polymers (a)-(o) above. In another particular aspect of this embodiment, the ionomer composition optionally comprises one or more non-ionomeric polymers, wherein the total amount of non-ionomeric polymer(s) is less than 50 wt %, based on the total polymeric weight of the composition, and wherein the non-ionomeric polymer(s) are selected from maleic anhydride-grafted polyethylenes, polyesters, polyamides, polyethers and combinations of two or more thereof.

The ionomer composition used to form one layer may be the same as or different than the ionomer composition used to form another layer.

Suitable ionomers include partially neutralized ionomers and highly neutralized ionomers (HNPs), including ionomers formed from blends of two or more partially neutralized ionomers, blends of two or more highly neutralized ionomers, and blends of one or more partially neutralized ionomers with one or more highly neutralized ionomers. For purposes of the present disclosure, “HNP” refers to an acid copolymer after at least 80% of all acid groups present in the composition are neutralized. Preferred ionomers are salts of O/X- and O/X/Y-type acid copolymers, wherein O is an α-olefin, X is a C₃-C₈ α,β-ethylenically unsaturated carboxylic acid, and Y is a softening monomer. O is preferably selected from ethylene and propylene. X is preferably selected from methacrylic acid, acrylic acid, ethacrylic acid, crotonic acid, and itaconic acid. Methacrylic acid and acrylic acid are particularly preferred. Y is preferably selected from (meth) acrylate and alkyl (meth) acrylates wherein the alkyl groups have from 1 to 8 carbon atoms, including, but not limited to, n-butyl (meth) acrylate, isobutyl (meth) acrylate, methyl (meth) acrylate, and ethyl (meth) acrylate. Particularly preferred O/X/Y-type copolymers are ethylene/(meth) acrylic acid/n-butyl (meth) acrylate, ethylene/(meth) acrylic acid/isobutyl (meth) acrylate, ethylene/(meth) acrylic acid/methyl (meth) acrylate, and ethylene/(meth) acrylic acid/ethyl (meth) acrylate. As used herein, “(meth) acrylic acid” means methacrylic acid and/or acrylic acid. Likewise, “(meth) acrylate” means methacrylate and/or acrylate. The a-olefin is typically present in the acid copolymer in an amount of 15 wt % or greater, or 25 wt % or greater, or 40 wt % or greater, or 60 wt % or greater, based on the total weight of the acid copolymer. The acid is typically present in the acid copolymer in an amount of 6 wt % or greater, or 9 wt % or greater, or 10 wt % or greater, or 11 wt % or greater, or 15 wt % or greater, or 16 wt % or greater, or in an amount within a range having a lower limit of 1 or 4 or 5 or 6 or 8 or 10 or 11 or 12 or 15 wt % and an upper limit of 15 or 16 or 17 or 19 or 20 or 20.5 or 21 or 25 or 30 or 35 or 40 wt %, based on the total weight of the acid copolymer. The optional softening monomer is typically present in the acid copolymer in an amount within a range having a lower limit of 0 or 1 or 3 or 5 or 11 or 15 or 20 wt % and an upper limit of 23 or 25 or 30 or 35 or 50 wt %, based on the total weight of the acid copolymer.

The acid copolymer is at least partially neutralized with a cation source, optionally in the presence of a high molecular weight organic acid, such as those disclosed in U.S. Pat. No. 6,756,436, the entire disclosure of which is hereby incorporated herein by reference. The acid copolymer can be reacted with the optional high molecular weight organic acid and the cation source simultaneously, or prior to the addition of the cation source. Suitable cation sources include, but are not limited to, metal ion sources, such as compounds of alkali metals, alkaline earth metals, transition metals, and rare earth elements; ammonium salts and monoamine salts; and combinations thereof. Preferred cation sources are compounds of magnesium, sodium, potassium, cesium, calcium, barium, manganese, copper, zinc, lead, tin, aluminum, nickel, chromium, lithium, and rare earth metals.

Suitable ionomers are further disclosed, for example, in U.S. Patent Application Publication Nos. 2005/0049367, 2005/0148725, 2005/0020741, 2004/0220343, and 2003/0130434, and U.S. Pat. Nos. 5,587,430, 5,691,418, 5,866,658, 6,100,321, 6,562,906, 6,653,382, 6,756,436, 6,777,472, 6,762,246, 6,815,480, 6,894,098, 6,919,393, 6,953,820, 6,994,638, 7,375,151, and 7,652,086, the entire disclosures of which are hereby incorporated herein by reference.

Non-limiting examples of suitable commercially available thermoplastics are Surlyn® ionomers and DuPont® HPF 1000 and HPF 2000 highly neutralized polymers, commercially available from E. I. du Pont de Nemours and Company; Clarix® ionomers, commercially available from A. Schulman, Inc.; lotek® ionomers, commercially available from ExxonMobil Chemical Company; and Amplify® IO ionomers, commercially available from The Dow Chemical Company; Amplify® GR functional polymers and Amplify® TY functional polymers, commercially available from The Dow Chemical Company; Fusabond® functionalized polymers, commercially available from E. I. du Pont de Nemours and Company; Exxelor® maleic anhydride grafted polymers, commercially available from ExxonMobil Chemical Company; ExxonMobil® PP series polypropylene impact copolymers, commercially available from ExxonMobil Chemical Company; Vistamaxx® propylene-based elastomers, commercially available from ExxonMobil Chemical Company; Exact® plastomers, commercially available from ExxonMobil Chemical Company; Santoprene® thermoplastic vulcanized elastomers, commercially available from ExxonMobil Chemical Company; Kraton® styrenic block copolymers, commercially available from Kraton Performance Polymers Inc.; Septon® styrenic block copolymers, commercially available from Kuraray Co., Ltd.; Lotader® ethylene acrylate based polymers, commercially available from Arkema Corporation; Polybond® grafted polyethylenes and polypropylenes, commercially available from Chemtura Corporation; Pebax® polyether and polyester amides, commercially available from Arkema Inc.; polyester-based thermoplastic elastomers, such as Hytrel® polyester elastomers, commercially available from E. I. du Pont de Nemours and Company, and Riteflex® polyester elastomers, commercially available from Ticona; Estane® thermoplastic polyurethanes, commercially available from The

Lubrizol Corporation; Grivory® polyamides and Grilamid® polyamides, commercially available from EMS Grivory; Zytel® polyamide resins and Elvamide® nylon multipolymer resins, commercially available from E. I. du Pont de Nemours and Company; Elvaloy® acrylate copolymer resins, commercially available from E. I. du Pont de Nemours and Company; Elastollan® polyurethane-based thermoplastic elastomers, commercially available from BASF; Xylex® polycarbonate/polyester blends, commercially available from SABIC Innovative Plastics; and combinations of two or more thereof.

Thermoplastic compositions of the present invention optionally include additive(s) and/or filler(s) in an amount of 50 wt % or less, or 30 wt % or less, or 20 wt % or less, or 15 wt % or less, based on the total weight of the thermoplastic composition. Suitable additives and fillers include, but are not limited to, chemical blowing and foaming agents, optical brighteners, coloring agents, fluorescent agents, whitening agents, UV absorbers, light stabilizers, defoaming agents, processing aids, antioxidants, stabilizers, softening agents, fragrance components, plasticizers, impact modifiers, TiO₂, acid copolymer wax, surfactants, performance additives (e.g., A-C® performance additives, particularly A-C® low molecular weight ionomers and copolymers, A-C® oxidized polyethylenes, and A-C® ethylene vinyl acetate waxes, commercially available from Honeywell International Inc.), fatty acid amides (e.g., ethylene bis-stearamide and ethylene bis-oleamide), fatty acids and salts thereof (e.g., stearic acid, oleic acid, zinc stearate, magnesium stearate, zinc oleate, and magnesium oleate), and fillers, such as zinc oxide, tin oxide, barium sulfate, zinc sulfate, calcium oxide, calcium carbonate, zinc carbonate, barium carbonate, tungsten, tungsten carbide, silica, lead silicate, clay, mica, talc, nano-fillers, carbon black, glass flake, milled glass, flock, fibers, and mixtures thereof. Suitable additives are more fully described in, for example, U.S. Patent Application Publication No. 2003/0225197, the entire disclosure of which is hereby incorporated herein by reference. In a particular embodiment, the total amount of additive(s) and filler(s) present in the thermoplastic composition is 20 wt % or less, or 15 wt % or less, or 12 wt % or less, or 10 wt % or less, or 9 wt % or less, or 6 wt % or less, or 5 wt % or less, or 4 wt % or less, or 3 wt % or less, or within a range having a lower limit of 0 or 2 or 3 or 5 wt %, based on the total weight of the thermoplastic composition, and an upper limit of 9 or 10 or 12 or 15 or 20 wt %, based on the total weight of the thermoplastic composition. In a particular aspect of this embodiment, the thermoplastic composition includes filler(s) selected from carbon black, micro- and nano-scale clays and organoclays, including (e.g., Cloisite® and Nanofil® nanoclays, commercially available from Southern Clay Products, Inc.; Nanomax® and Nanomer® nanoclays, commercially available from Nanocor, Inc., and Perkalite® nanoclays, commercially available from Akzo Nobel Polymer Chemicals), micro- and nano-scale talcs (e.g., Luzenac HAR® high aspect ratio talcs, commercially available from Luzenac America, Inc.), glass (e.g., glass flake, milled glass, microglass, and glass fibers), micro- and nano-scale mica and mica-based pigments (e.g., Iriodin® pearl luster pigments, commercially available from The Merck Group), and combinations thereof. Particularly suitable combinations of fillers include, but are not limited to, micro-scale filler(s) combined with nano-scale filler(s), and organic filler(s) with inorganic filler(s).

Ionomer compositions of the present invention, in the unfilled form, typically have a specific gravity of from 0.95 g/cm³ to 0.99 g/cm³. Thus, in some embodiments of the present invention, it is desirable to add a filler, flake, fiber, particle, or the like to the ionomer composition to achieve an overall golf ball specific gravity of from 1.10 g/cm³ to 1.20 g/cm³ and/or to adjust the weight distribution within the ball, as further disclosed, for example, in U.S. Pat. Nos. 6,494,795, 6,547,677, 6,743,123, 7,074,137, and 6,688,991, the entire disclosures of which are hereby incorporated herein by reference. In a particular embodiment, the ionomer composition comprises a density adjusting filler selected from precipitated hydrated silica, clay, talc, asbestos, glass fibers, aramid fibers, mica, calcium metasilicate, zinc sulfate, barium sulfate, zinc sulfide, lithopone, silicates, silicon carbide, diatomaceous earth, polyvinyl chloride, carbonates (e.g., calcium carbonate, zinc carbonate, barium carbonate, and magnesium carbonate), metals (e.g., titanium, tungsten, aluminum, bismuth, nickel, molybdenum, iron, lead, copper, boron, cobalt, beryllium, zinc, and tin), metal alloys (e.g., steel, brass, bronze, boron carbide whiskers, and tungsten carbide whiskers), oxides (e.g., zinc oxide, tin oxide, iron oxide, calcium oxide, aluminum oxide, titanium dioxide, magnesium oxide, and zirconium oxide), metal stearates, particulate carbonaceous materials (e.g., graphite, carbon black, cotton flock, natural bitumen, cellulose flock, and leather fiber), microballoons (e.g., glass and ceramic), fly ash, core material that is ground and recycled, nanofillers, and combinations thereof. Thermoplastic compositions of the present invention optionally include one or more melt flow modifiers selected from fatty acids and fatty acid salts, including, but not limited to, those disclosed in U.S. Pat. No. 5,306,760, the entire disclosure of which is hereby incorporated herein by reference; fatty amides and salts thereof; polyhydric alcohols, including, but not limited to, those disclosed in U.S. Pat. No. 7,365,128, and U.S. Patent Application Publication No. 2010/0099514, the entire disclosures of which are hereby incorporated herein by reference;

polylactic acids, including, but not limited to, those disclosed in U.S. Pat. No. 7,642,319, the entire disclosure of which is hereby incorporated herein by reference; and the modifiers disclosed in U.S. Patent Application Publication No. 2010/0099514 and 2009/0203469, the entire disclosures of which are hereby incorporated herein by reference. Optional flow enhancing additives also include, but are not limited to, montanic acids, esters of montanic acids and salts thereof, bis-stearoylethylenediamine, mono- and polyalcohol esters such as pentaerythritol tetrastearate, zwitterionic compounds, and metallocene-catalyzed polyethylene and polypropylene wax, including maleic anhydride modified versions thereof, amide waxes and alkylene diamides such as bistearamides. Particularly suitable fatty amides include, but are not limited to, saturated fatty acid monoamides (e.g., lauramide, palmitamide, arachidamide behenamide, stearamide, and 12-hydroxy stearamide); unsaturated fatty acid monoamides (e.g., oleamide, erucamide, and ricinoleamide); N-substituted fatty acid amides (e.g., N-stearyl stearamide, N-behenyl behenamide, N-stearyl behenamide, N-behenyl stearamide, N-oleyl oleamide, N-oleyl stearamide, N-stearyl oleamide, N-stearyl erucamide, erucyl erucamide, and erucyl stearamide, N-oleyl palmitamide, methylol amide (more preferably, methylol stearamide, methylol behenamide); saturated fatty acid bis-amides (e.g., methylene bis-stearamide, ethylene bis-stearamide, ethylene bis-isostearamide, ethylene bis-hydroxystearamide, ethylene bis-behenamide, hexamethylene bis-stearamide, hexamethylene bis-behenamide, hexamethylene bis-hydroxystearamide, N,N′-distearyl adipamide, and N,N′-distearyl sebacamide); unsaturated fatty acid bis-amides (e.g., ethylene bis-oleamide, hexamethylene bis-oleamide, N,N′-dioleyl adipamide, N,N′-dioleyl sebacamide); and saturated and unsaturated fatty acid tetra amides, stearyl erucamide, ethylene bis stearamide and ethylene bis oleamide. Suitable examples of commercially available fatty amides include, but are not limited to, Kemamide® fatty acids, such as Kemamide® B (behenamide/arachidamide), Kemamide® W40 (N,N′-ethylenebisstearamide), Kemamide® P181 (oleyl palmitamide), Kemamide® S (stearamide), Kemamide® U (oleamide), Kemamide® E (erucamide), Kemamide® O (oleamide), Kemamide® W45 (N,N′-ethylenebisstearamide), Kenamide® W20 (N,N′-ethylenebisoleamide), Kemamide® E180 (stearyl erucamide), Kemamide® E221 (erucyl erucamide), Kemamide® S180 (stearyl stearamide), Kemamide® S221 (erucyl stearamide), commercially available from Chemtura Corporation; and Crodamide® fatty amides, such as Crodamide® OR (oleamide), Crodamide® ER (erucamide), Crodamide® SR (stereamide), Crodamide® BR (behenamide), Crodamide® 203 (oleyl palmitamide), and Crodamide® 212 (stearyl erucamide), commercially available from Croda Universal Ltd.

Thermoplastic layers are optionally treated or admixed with a thermoset diene composition to reduce or prevent flow upon overmolding. Optional treatments may also include the addition of peroxide to the material prior to molding, or a post-molding treatment with, for example, a crosslinking solution, electron beam, gamma radiation, isocyanate or amine solution treatment, or the like. Such treatments may prevent a thermoplastic layer from melting and flowing or “leaking” out at the mold equator, as thermoset layers are molded thereon at a temperature necessary to crosslink the thermoset layer, which is typically from 280° F. to 360° F. for a period of about 5 to 30 minutes.

In a particular embodiment, the cover includes a thermoset layer. Suitable thermoset compositions include thermoset polyurethanes, polyureas, and polyurethane-polyurea hybrids (i.e., blends and copolymers of polyurethanes and polyureas); polybutadiene rubber; polyisoprene rubber; natural rubber; styrene-butadiene rubber; and combinations thereof.

Thermoplastic and thermoset polyurethanes, polyureas, and polyurethane-polyurea hybrids are particularly suitable for forming cover layers of the present invention. Suitable polyurethane and polyurea cover compositions are formed from the reaction product of at least one isocyanate and at least one curing agent or the reaction product of at least one isocyanate, at least one polyol, and at least one curing agent. Non-limiting examples of particularly suitable isocyanates include 2,2′-, 2,4′-, and 4,4′-diphenylmethane diisocyanate (MDI); 3,3′-dimethyl-4,4′-biphenyl diisocyanate (TODI); toluene diisocyanate (TDI); polymeric MDI; carbodimide-modified liquid 4,4′-diphenylmethane diisocyanate; para-phenylene diisocyanate (PPDI); metaphenylene diisocyanate (MPDI); triphenylmethane-4,4′-, and triphenylmethane-4,4″-triisocyanate; napthylene-1,5,-diisocyanate; 2,4′-, 4,4′-, and 2,2′-biphenyl diisocyanate;

polyphenylene polymethylene polyisocyanate (PMDI) (also known as polymeric PMDI); ethylene diisocyanate; propylene-1,2-diisocyanate; tetramethylene diisocyanate; tetramethylene-1,4-diisocyanate; 1,6-hexamethylene diisocyanate (HDI); octamethylene diisocyanate; decamethylene diisocyanate; 2,2,4-trimethylhexamethylene diisocyanate; 2,4,4-trimethylhexamethylene diisocyanate; dodecane-1,12-diisocyanate; cyclobutane-1,3-diisocyanate; cyclohexane-1,2-diisocyanate; cyclohexane-1,3-diisocyanate; cyclohexane- 1,4-diisocyanate; methylcyclohexylene diisocyanate (HTDI); 2,4-methylcyclohexane diisocyanate; 2,6-methylcyclohexane diisocyanate; 4,4′-dicyclohexyl diisocyanate; 2,4′-dicyclohexyl diisocyanate; 1,3,5-cyclohexane triisocyanate; isocyanatomethylcyclohexane isocyanate; 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane; isocyanatoethylcyclohexane isocyanate; bis(isocyanatomethyl)-cyclohexane diisocyanate; 4,4′-bis(isocyanatomethyl) dicyclohexane; 2,4′-bis(isocyanatomethyl) dicyclohexane; isophorone diisocyanate (IPDI); triisocyanate of HDI; triisocyanate of 2,2,4-trimethyl-1,6-hexane diisocyanate (TMDI); 4,4′-dicyclohexylmethane diisocyanate (H12MDI); 2,4-hexahydrotoluene diisocyanate; 2,6-hexahydrotoluene diisocyanate; aromatic aliphatic isocyanate, such as 1,2-, 1,3-, and 1,4-xylene diisocyanate; meta-tetramethylxylene diisocyanate (m-TMXDI); para-tetramethylxylene diisocyanate (p-TMXDI); trimerized isocyanurate of any polyisocyanate, such as isocyanurate of toluene diisocyanate, trimer of diphenylmethane diisocyanate, trimer of tetramethylxylene diisocyanate, isocyanurate of hexamethylene diisocyanate, isocyanurate of isophorone diisocyanate, and mixtures thereof; dimerized uretdione of any polyisocyanate, such as uretdione of toluene diisocyanate, uretdione of hexamethylene diisocyanate, and combinations thereof; modified polyisocyanate derived from the above isocyanates and polyisocyanates; and combinations thereof. Non-limiting examples of particularly suitable polyols include polyether polyols (e.g., polytetramethylene ether glycol (PTMEG); copolymers of polytetramethylene ether glycol and 2-methyl-1,4-butane diol (PTG-L); poly(oxyethylene) glycol; poly(oxypropylene) glycol; ethylene oxide capped (polyoxypropylene) glycol; and poly(oxypropylene oxyethylene) glycol); polycaprolactone polyols (e.g., diethylene glycol initiated polycaprolactone; propylene glycol initiated polycaprolactone; 1,4-butanediol initiated polycaprolactone; 1,6-hexanediol initiated polycaprolactone; trimethylol propane initiated polycaprolactone; neopentyl glycol initiated polycaprolactone; polytetramethylene ether glycol initiated polycaprolactone; ethylene glycol initiated polycaprolactone; and dipropylene glycol initiated polycaprolactone); polyester polyols (e.g., polyethylene adipate glycol; polyethylene propylene adipate glycol; polybutylene adipate glycol; polyethylene butylene adipate glycol; polyhexamethylene adipate glycol; polyhexamethylene butylene adipate glycol; o-phthalate-1,6-hexanediol polyester polyol; and polyethylene terephthalate polyester polyols); polycarbonate polyols (e.g., poly(phthalate carbonate) glycol, poly(hexamethylene carbonate) glycol, and polycarbonate polyols containing bisphenol A); hydrocarbon polyols (e.g., hydroxy-terminated liquid isoprene rubber (LIR), hydroxy-terminated polybutadiene polyol, hydroxy-terminated polyolefin polyols, and hydroxy-terminated hydrocarbon polyols); and combinations thereof. The hydrocarbon chain of the polyol can have saturated or unsaturated bonds, or substituted or unsubstituted aromatic and cyclic groups. Suitable curing agents include, but are not limited to, hydroxy-terminated curing agents, amine-terminated curing agents, and combinations thereof. The curing agent may be saturated or unsaturated. Non-limiting examples of suitable curatives include 1,4-butanediol; 1,3-butanediol; 1,2-butanediol; 2,3-butanediol; 2,3-dimethyl-2,3-butanediol; propylene glycol, dipropylene glycol; polypropylene glycol; 2-methyl-1,3-propanediol; 2-methyl-1,4-butanediol;

ethylene glycol; diethylene glycol; polyethylene glycol; resorcinol-di(beta-hydroxyethyl)ether and its derivatives; hydroquinone-di(beta-hydroxyethyl)ether and derivatives thereof; 2-propano1-1,1′-phenylaminobis; trimethylolpropane; 4,4′-methylenebis(2-chloroaniline); 3,5-dimethylthio-2,4-toluenediamine; 3,5-dimethylthio-2,6-toluenediamine; 4,4′-methylenebis(2-ethylaniline); 4,4′-bis-(sec-butylamino)-diphenylmethane; 1,3-bis-(2-hydroxyethoxy)benzene; 1,3-bis-[2-(2-hydroxyethoxy)ethoxy]benzene; 1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}benzene; 1,4-bis-(sec-butylamino) benzene; 1,2-bis-(sec-butylamino)benzene; 3,5-diethyltoluene-2,4-diamine; 3,5-diethyltoluene-2,6-diamine; tetra-(2-hydroxypropyl)-ethylenediamine; N,N′-dialkyldiamino diphenyl methane; trimethyleneglycol-di-p-aminobenzoate; polytetramethyleneoxide-di-p-aminobenzoate; 4,4′-methylene bis-(3-chloro-2,6-diethylaniline); 1,4-cyclohexyldimethylol; 2-methylpentamethylene diamine; isomers and mixtures of diaminocyclohexane; isomers and mixtures of cyclohexane bis(methylamine); polytetramethylene ether glycol; isomers and mixtures of cyclohexyldimethylol; triisopropanolamine; diethylene triamine; triethylene tetramine; tetraethylene pentamine; propylene diamine; dipropylene triamine; 1,3-diaminopropane; dimethylamino propylamine;

diethylamino propylamine; diethylene glycol bis-(aminopropyl)ether; imido-bis-(propylamine); monoethanolamine; diethanolamine; triethanolamine; monoisopropanolamine; diisopropanolamine; isophoronediamine; N,N′-diisopropyl-isophoronediamine; polyoxypropylene diamine; propylene oxide-based triamine; 3,3′-dimethyl-4,4′-diaminocyclohexylmethane; 1,5-pentanediol; 1,6-hexanediol; glycerol; 1,3-bis-(2-hydroxyethoxy)cyclohexane; 1,3-bis-[2-(2-hydroxyethoxy)ethoxy]cyclohexane; 1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}cyclohexane; N,N,N′,N′-tetra-(2-hydroxypropyl-ethylene) diamine; ethylene diamine; hexamethylene diamine; 1-methyl-2,6-cyclohexyl diamine; 2,2,4- and 2,4,4-trimethyl-1,6-hexanediamine; 4,4′-bis-(sec-butylamino)-dicyclohexylmethane and derivatives thereof; 1,4-bis-(sec-butylamino)-cyclohexane; 1,2-bis-(sec-butylamino)-cyclohexane; 4,4′-dicyclohexylmethane diamine; and combinations thereof.

Suitable polyurethanes and polyureas are further disclosed, for example, in U.S. Pat. Nos. 5,334,673, 5,484,870, 6,506,851, 6,528,578, 6,756,436, 6,835,794, 6,867,279, 6,960,630, 7,105,623, and 7,148,278; U.S. Patent Application Publication Nos. 2012/0100935, 2012/0015758, and 2007/0117923; and U.S. patent application Ser. No. 13/534,264 to Michalewich; the entire disclosures of which are hereby incorporated herein by reference.

Golf Ball Constructions

Golf balls of the present invention comprise a thermoplastic core encased in three or more thermoplastic intermediate layers, and a cover disposed about the encased core.

The core is a single or multilayer core formed from one or more layers of the same or different thermoplastic materials. In a particular embodiment, the core has one or more of the following properties:

(a) each core layer is formed from an ionomer composition, preferably including at least one layer formed from an HNP composition wherein at least 80%, or at least 90%, or at least 95%, or at least 99% of all acid groups present in the composition are neutralized;

(b) an overall core compression of 90 or less, or less than 90, or 75 or less, or less than 75, or 60 or less, or less than 60, or 50 or less, or less than 50, or 40 or less, or less than 40, or 30 or less, or less than 30, or 20 or less, or less than 20, or an overall core compression within a range having a lower limit of 10 or 20 or 30 or 35 or 40 and an upper limit of 50 or 60 or 70 or 80 or 90;

(c) an overall core diameter of 0.75 inches or greater, or 0.80 inches or greater, or 0.90 inches, or 1.00 inches or greater, or 0.115 inches or greater, or 1.25 inches or greater, or 1.30 inches or greater, or 1.35 inches or greater, or an overall core diameter within a range having a lower limit of 0.50 inches or 0.75 inches or 0.80 inches or 0.90 inches or 1.00 inches or 1.10 inches or 1.15 inches or 1.20 inches or 1.25 inches or 1.30 inches or 1.35 inches and an upper limit of 1.35 inches or 1.39 inches or 1.40 inches or 1.45 inches or 1.48 inches or 1.50 inches or 1.55 inches or 1.58 inches or 1.60 inches; and

(d) each core layer has a material hardness of less than 65 Shore D, or 63 Shore D or less, or less than 63 Shore D, or 60 Shore D or less, or less than 60 Shore D, or 57 Shore D or less, or less than 57 Shore D.

The core is enclosed by at least three thermoplastic intermediate layers including a soft and thick layer, a first stiff and thin layer, and a second stiff and thin layer. In one embodiment, the soft and thick intermediate layer is disposed between the first stiff and thin intermediate layer and the second stiff and thin intermediate layer. In another embodiment, the first stiff and thin intermediate layer is disposed between the soft and thick intermediate layer and the second stiff and thin intermediate layer.

The soft and thick intermediate layer has a material hardness less than that of each of the stiff and thin layers, and has a thickness greater than that of each of the stiff and thin layers. The soft and thick intermediate layer is typically formed from a composition having a material hardness of 65 Shore D or less. In a particular embodiment, the soft and thick intermediate layer is formed from a composition having a material hardness of less than 65 Shore D, or 63 Shore D or less, or less than 63 Shore D, or 60 Shore D or less, or less than 60 Shore D, or 59 Shore D or less, or less than 59 Shore D, or 57 Shore D or less, or less than 57 Shore D. In a particular aspect of this embodiment, the soft and thick intermediate layer is formed from an HNP composition wherein at least 80%, or at least 90%, or at least 95%, or at least 99% of all acid groups present in the composition are neutralized. The soft and thick intermediate layer typically has a thickness of from 0.025 inches to 0.125 inches. In a particular embodiment, the soft and thick intermediate layer has a thickness within a range having a lower limit of 0.025 inches or 0.030 inches or 0.035 inches or 0.040 inches or 0.045 inches or 0.050 inches 0.060 inches or 0.070 inches or 0.075 inches and an upper limit of 0.075 inches or 0.080 inches or 0.085 inches or 0.090 inches or 0.100 inches or 0.110 inches or 0.120 inches or 0.125 inches.

The stiff and thin intermediate layers are typically formed from compositions having a material hardness of 60 Shore D or greater. The material hardness of one stiff and thin intermediate layer may be the same as or different than the material hardness of another stiff and thin intermediate layer. In a particular embodiment, each stiff and thin intermediate layer has a material hardness of 60 Shore D or greater, or greater than 60 Shore D, or 63 Shore D or greater, or greater than 63 Shore D, or 65 Shore D or greater, or greater than 65 Shore D, or 69 Shore D or greater, or greater than 69 Shore D, or 70 Shore D or greater, or a material hardness within a range having a lower limit of 60 or 63 or 65 or 67 or 69 or 70 Shore D and an upper limit of 70 or 73 or 75 or 78 or 80 Shore D. In a particular aspect of this embodiment, the first stiff and thin intermediate layer is enclosed in the second stiff and thin intermediate layer, the second stiff and thin intermediate layer has a material hardness greater than that of the first stiff and thin intermediate layer, and the difference between the material hardness of the first and second stiff and thin intermediate layers is at least 1 Shore D, or at least 2 Shore D, or at least 3 Shore D, or at least 5 Shore D. In another particular aspect of this embodiment, the first stiff and thin intermediate layer is enclosed in the soft and thick intermediate layer, and the soft and thick intermediate layer is enclosed in the second stiff and thin intermediate layer; the second stiff and thin intermediate layer has a material hardness greater than that of the first stiff and thin intermediate layer, and the difference between the material hardness of the first and second stiff and thin intermediate layers is at least 1 Shore D, or at least 2 Shore D, or at least 3 Shore D, or at least 5 Shore D.

The composition used to form one stiff and thin intermediate layer may be the same as or different than the composition used to form another stiff and thin intermediate layer. In a particular embodiment, each stiff and thin intermediate layer is formed from a composition independently selected from ionomer composition wherein less than 80%, or 75% or less, or less than 75%, or 70% or less, or less than 70%, or 65% or less, or less than 65%, or 50% or less, or less than 50% of all acid groups present in the composition are neutralized.

The thickness of one stiff and thin intermediate layer may be the same as or different than the thickness of another stiff and thin intermediate layer. Each stiff and thin intermediate layer typically has a thickness of from 0.010 inches to 0.070 inches. In a particular embodiment, each stiff and thin intermediate layer has a thickness within a range having a lower limit of 0.010 inches or 0.015 inches or 0.020 inches or 0.025 inches or 0.030 inches or 0.035 inches and an upper limit of 0.040 inches or 0.050 inches or 0.070 inches.

The core and intermediate layers are enclosed by a single or multilayer cover. Each cover layer is formed from a thermoplastic or thermoset composition as disclosed above. In a particular embodiment, the cover includes an outermost layer formed from a thermoset polyurethane, polyurea, or polyurethane-urea hybrid. The thermoset polyurethane, polyurea, or polyurethane-urea hybrid is preferably a castable or reaction injection moldable thermoset composition. The use of a castable, reactive material, when applied in a fluid form, makes it possible to obtain very thin outer cover layers. The castable, reactive liquid employed to form the urethane elastomer material can be applied over the golf ball subassembly (i.e., core encaesd by intermediate layers) using a variety of application techniques such as spraying, dipping, spin coating, or flow coating methods which are well known in the art. Suitable non-limiting techniques for forming thin polyurethane outer cover layers are disclosed in U.S. Pat. Nos. 5,733,428, 5,006,297, 5,334,673 and 8,202,176, the entire disclosures of which are hereby incorporated herein by reference. The outer cover is preferably formed around the golf ball subassembly by mixing and introducing the material in mold halves. It is important that the viscosity be measured over time, so that the subsequent steps of filling each mold half, introducing the golf ball subassembly into one half and closing the mold can be properly timed for accomplishing centering of the golf ball subassembly, fusion of the cover halves, and achieving overall uniformity. Suitable viscosity range of the curing urethane mix for introducing cores into the mold halves is determined to be approximately between about 2,000 cP and about 30,000 cP, with the preferred range of about 8,000 cP to about 15,000 cP. Other methods of molding include reaction injection molding (RIM) where two liquid components are injected into a mold holding a pre-positioned core. The liquid components react to form a solid, thermoset polymeric composition, typically a polyurethane or polyurea.

The cover typically has an overall thickness of from 0.010 inches to 0.500 inches. In a particular embodiment, the cover has an overall thickness within a range having a lower limit of 0.010 or 0.020 or 0.025 or 0.030 or 0.040 or 0.045 inches and an upper limit of 0.050 or 0.060 or 0.070 or 0.075 or 0.080 or 0.090 or 0.100 or 0.150 or 0.200 or 0.300 or 0.500 inches. In another particular embodiment, the cover is a single layer having a thickness of from 0.025 inches to 0.035 inches. In another particular embodiment, the cover comprises an outer cover layer formed from a thermoset polyurethane, polyurea, or polyurethane-urea hybrid and having a thickness of from 0.025 inches to 0.035 inches.

In one embodiment, the present invention is directed to a golf ball comprising:

-   -   a thermoplastic core enclosed in     -   a first stiff and thin thermoplastic intermediate layer enclosed         in     -   a soft and thick thermoplastic intermediate layer enclosed in     -   a second stiff and thin thermoplastic intermediate layer         enclosed in     -   an outer cover layer layer.

In another embodiment, the present invention is directed to a golf ball comprising:

-   -   a thermoplastic core enclosed in     -   a soft and thick thermoplastic intermediate layer enclosed in     -   a first stiff and thin thermoplastic intermediate layer enclosed         in     -   a second stiff and thin thermoplastic intermediate layer         enclosed in     -   an outer cover layer layer.

In a particular aspect of the above embodiments, the core is a single layer formed from an ionomer composition, particularly an HNP composition, and having a compression of 60 or less, and a diameter of from 1.20 inches to 1.50 inches. In another particular aspect of the above embodiments, the core is a dual core comprising an inner core layer and an outer core layer, wherein the inner core layer and outer core layer are formed from different ionomer compositions independently selected from partially neutralized ionomers and HNPs, and wherein the dual core has an overall dual core compression of 60 or less, and an overall dual core diameter of from 1.20 inches to 1.50 inches.

In another particular aspect of the above embodiments, the first and second stiff and thin intermediate layers are formed from the same or different thermoplastic compositions, and the first and second stiff and thin intermediate layers each have one or more properties independently selected from:

(a) the layer is formed from a partially neutralized ionomer composition wherein the ionomer is selected from salts of O/X- and O/X/Y-type acid copolymers, and wherein the acid copolymer has an acid content of at least 10 wt %, or at least 15 wt %, based on the total weight of the acid copolymer;

(b) less than 80% of all acid groups present in the composition are neutralized with a cation source, and wherein the cation source is selected from compounds of zinc, sodium, lithium, magnesium, and combinations of two or more thereof;

(c) less than 80% of all acid groups present in the composition are neutralized with a cation source, and wherein the cation source is zinc/sodium;

(d) less than 80% of all acid groups present in the composition are neutralized with a cation source, and wherein the cation source is sodium/lithium;

(e) the layer is formed from a composition comprising a blend of Surlyn® 7940/Surlyn® 8940, optionally including a melt flow modifier;

(f) the layer is formed from a composition comprising a blend of a first high acid ionomer and a second high acid ionomer, wherein the first high acid ionomer is neutralized with a different cation than the second high acid ionomer (e.g., 50/50 blend of Surlyn® 8150 and Surlyn® 9150), optionally including one or more melt flow modifiers such as an ionomer, ethylene-acid copolymer or ester terpolymer; and

(g) the layer has a material hardness of 60 Shore D or greater, or a material hardness of from 63 Shore D to 80 Shore D; and

(h) the layer has a thickness within a range having a lower limit of 0.010 inches or 0.025 inches and an upper limit of 0.040 inches or 0.070 inches.

Surlyn 8150®, Surlyn® 8940, and Surlyn® 8140 are different grades of E/MAA copolymer in which the acid groups have been partially neutralized with sodium ions. Surlyn® 9650, Surlyn® 9910, Surlyn® 9150, and Surlyn® 9120 are different grades of E/MAA copolymer in which the acid groups have been partially neutralized with zinc ions. Surlyn® 7940 is an E/MAA copolymer in which the acid groups have been partially neutralized with lithium ions. Surlyn® 6320 is a very low modulus magnesium ionomer with a medium acid content. Nucrel® 960 is an E/MAA copolymer resin nominally made with 15 wt % methacrylic acid. Surlyn® ionomers, Fusabond® polymers, and Nucrel® copolymers are commercially available from E. I. du Pont de Nemours and Company.

In another particular aspect of the above embodiments, the soft and thick intermediate layer is formed from an HNP composition wherein at least 80%, or at least 90%, or at least 95%, or at least 99% of all acid groups present in the composition are neutralized, and has a thickness of from 0.03 inches to 0.09 inches and a material hardness of less than 60 Shore D.

In another particular aspect of the above embodiments, the cover is a single layer, preferably formed from castable or reaction injection moldable thermosetting polyurethane, polyurea, or copolymer or hybrid of polyurethane/polyurea, and preferably has a surface hardness of 60 Shore D or less, a material hardness of 60 Shore D or less, and a thickness within a range having a lower limit of 0.010 or 0.015 or 0.020 or 0.025 inches and an upper limit of 0.035 or 0.040 or 0.050 inches.

Golf balls of the present invention typically have an overall ball compression of from 50 to 120. In a particular embodiment, the present invention provides golf balls having an overall ball compression within a range having a lower limit of 50 or 60 or 70 or 80 and an upper limit of 105 or 110 or 115 or 120.

Golf balls of the present invention typically have an overall coefficient of restitution (COR) of 0.750 or greater. In a particular embodiment, the present invention provides golf balls having an overall COR of 0.750 or greater, or greater than 0.750, or 0.790 or greater, or greater than 0.790, or 0.800 or greater, or greater than 0.800.

For purposes of the present disclosure, “compression” refers to Atti compression and is measured according to a known procedure, using a digital Atti compression test device, wherein a piston is used to compress a ball against a spring. Conversion from Atti compression to Riehle (cores), Riehle (balls), 100 kg deflection, 130-10 kg deflection or effective modulus can be carried out according to the formulas given in Jeff Dalton's Compression by Any Other Name, Science and Golf IV, Proceedings of the World Scientific Congress of Golf (Eric Thain ed., Routledge, 2002).

For purposes of the present disclosure, COR is determined according to a known procedure wherein a sphere is fired from an air cannon at two given velocities and calculated at a velocity of 125 ft/s. Ballistic light screens are located between the air cannon and the steel plate at a fixed distance to measure sphere velocity. As the sphere travels toward the steel plate, it activates each light screen, and the time at each light screen is measured. This provides an incoming transit time period inversely proportional to the sphere's incoming velocity. The sphere impacts the steel plate and rebounds though the light screens, which again measures the time period required to transit between the light screens. This provides an outgoing transit time period inversely proportional to the sphere's outgoing velocity. COR is then calculated as the ratio of the outgoing transit time period to the incoming transit time period, COR=V_(out)N_(in)=T_(in)/T_(out).

For purposes of the present disclosure, the surface hardness of a golf ball layer is obtained from the average of a number of measurements taken from opposing hemispheres, taking care to avoid making measurements on the parting line of the sphere or on surface defects, such as holes or protrusions. Hardness measurements are made pursuant to ASTM D-2240 “Indentation Hardness of Rubber and Plastic by Means of a Durometer.” Because of the curved surface, care must be taken to insure that the sphere is centered under the durometer indentor before a surface hardness reading is obtained. A calibrated, digital durometer, capable of reading to 0.1 hardness units is used for all hardness measurements and is set to record the maximum hardness reading obtained for each measurement. The digital durometer must be attached to, and its foot made parallel to, the base of an automatic stand. The weight on the durometer and attack rate conform to ASTM D-2240.

For purposes of the present disclosure, material hardness is measured according to ASTM D2240 and generally involves measuring the hardness of a flat “slab” or “button” formed of the material. Hardness as measured directly on a golf ball (or other spherical surface) typically results in a different hardness value. This difference in hardness values is due to several factors including, but not limited to, ball construction (i.e., core type, number of core and/or cover layers, etc.), ball (or sphere) diameter, and the material composition of adjacent layers. It should be understood that the two measurement techniques are not linearly related and, therefore, one hardness value cannot easily be correlated to the other.

When numerical lower limits and numerical upper limits are set forth herein, it is contemplated that any combination of these values may be used.

All patents, publications, test procedures, and other references cited herein, including priority documents, are fully incorporated by reference to the extent such disclosure is not inconsistent with this invention and for all jurisdictions in which such incorporation is permitted.

While the illustrative embodiments of the invention have been described with particularity, it will be understood that various other modifications will be apparent to and can be readily made by those of ordinary skill in the art without departing from the spirit and scope of the invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the examples and descriptions set forth herein, but rather that the claims be construed as encompassing all of the features of patentable novelty which reside in the present invention, including all features which would be treated as equivalents thereof by those of ordinary skill in the art to which the invention pertains. 

What is claimed is:
 1. A golf ball comprising: a thermoplastic core having a diameter of from 0.900 inches to 1.550 inches and a compression of 90 or less; a first thermoplastic intermediate layer having a thickness of from 0.010 inches to 0.070 inches and a material hardness of from 60 Shore D to 80 Shore D; a second thermoplastic intermediate layer having a thickness of from 0.025 inches to 0.125 inches and a material hardness of 65 Shore D or less; a third thermoplastic intermediate layer having a thickness of from 0.010 inches to 0.070 inches and a material hardness of from 60 Shore D to 80 Shore D; and a cover; wherein the material hardness of the second thermoplastic intermediate layer is less than the material hardness of the first and third thermoplastic intermediate layers.
 2. The golf ball of claim 1, wherein the first intermediate layer and the third intermediate layer are each formed from a thermoplastic composition independently selected from partially-neutralized ionomer compositions comprising an E/X/Y-type copolymer, wherein E is ethylene, X is a C₃-C₈ α,β-ethylenically unsaturated carboxylic acid present in an amount of from 10 to 20 wt %, based on the total weight of the copolymer, and Y is an acrylate selected from alkyl acrylates and aryl acrylates present in an amount of from 0 wt % to 50 wt %, based on the total weight of the copolymer, wherein less than 80% of the acids present in the composition are neutralized with a metal ion source.
 3. The golf ball of claim 1, wherein the second intermediate layer is formed from a highly-neutralized thermoplastic composition comprising an E/X/Y-type copolymer, wherein E is ethylene, X is a C₃-C₈ α,β-ethylenically unsaturated carboxylic acid present in an amount of from 10 to 20 wt %, based on the total weight of the copolymer, and Y is an acrylate selected from alkyl acrylates and aryl acrylates present in an amount of from 0 wt % to 50 wt %, based on the total weight of the copolymer, wherein 80% or greater of the acids present in the composition are neutralized with a metal ion source.
 4. The golf ball of claim 1, wherein the core is a solid, single-layer core.
 5. The golf ball of claim 4, wherein the core has a compression of 60 or less.
 6. The golf ball of claim 1, wherein the core comprises an inner core layer formed from a first thermoplastic core composition and an outer core layer formed from a second thermoplastic core composition.
 7. The golf ball of claim 6, wherein the overall core has a compression of 60 or less.
 8. The golf ball of claim 1, wherein the thickness of the second intermediate core layer is greater than the thickness of the first thermoplastic intermediate layer and the thickness of the third thermoplastic intermediate layer.
 9. The golf ball of claim 8, wherein the thickness of the first thermoplastic intermediate layer is from 0.025 inches to 0.040 inches, the thickness of the second thermoplastic intermediate layer is from 0.035 inches to 0.075 inches, and the thickness of the second thermoplastic intermediate layer is from 0.025 inches to 0.040 inches.
 10. The golf ball of claim 1, wherein the surface hardness of the second thermoplastic intermediate layer is less than the surface hardness of the first thermoplastic intermediate layer, and wherein the surface hardness of the first thermoplastic intermediate layer is less than the surface hardness of the third thermoplastic intermediate layer.
 11. A golf ball comprising: a thermoplastic core having a diameter of from 0.900 inches to 1.550 inches and a compression of 90 or less; a first thermoplastic intermediate layer having a thickness of from 0.025 inches to 0.125 inches and a material hardness of 65 Shore D or less; a second thermoplastic intermediate layer having a thickness of from 0.010 inches to 0.070 inches and a material hardness of from 60 Shore D to 80 Shore D; a third thermoplastic intermediate layer having a thickness of from 0.010 inches to 0.070 inches and a material hardness of from 60 Shore D to 80 Shore D; and a cover; wherein the material hardness of the third thermoplastic intermediate layer is greater than the material hardness of the second thermoplastic intermediate layer; and wherein the material hardness of the second thermoplastic intermediate layer is greater than the material hardness of the first thermoplastic intermediate layer.
 12. The golf ball of claim 11, wherein the first intermediate layer is formed from a highly-neutralized thermoplastic composition comprising an E/X/Y-type copolymer, wherein E is ethylene, X is a C₃-C₈ α,β-ethylenically unsaturated carboxylic acid present in an amount of from 10 to 20 wt %, based on the total weight of the copolymer, and Y is an acrylate selected from alkyl acrylates and aryl acrylates present in an amount of from 0 wt % to 50 wt %, based on the total weight of the copolymer, wherein 80% or greater of the acids present in the composition are neutralized with a metal ion source.
 13. The golf ball of claim 11, wherein the second intermediate layer and the third intermediate layer are each formed from a thermoplastic composition independently selected from partially-neutralized ionomer compositions comprising an E/X/Y-type copolymer, wherein E is ethylene, X is a C₃-C₈ α,β-ethylenically unsaturated carboxylic acid present in an amount of from 10 to 20 wt %, based on the total weight of the copolymer, and Y is an acrylate selected from alkyl acrylates and aryl acrylates present in an amount of from 0 wt % to 50 wt %, based on the total weight of the copolymer, wherein less than 80% of the acids present in the composition are neutralized with a metal ion source.
 14. The golf ball of claim 1, wherein the core is a solid, single-layer core.
 15. The golf ball of claim 14, wherein the core has a compression of 60 or less.
 16. The golf ball of claim 11, wherein the core comprises an inner core layer formed from a first thermoplastic core composition and an outer core layer formed from a second thermoplastic core composition.
 17. The golf ball of claim 16, wherein the overall core has a compression of 60 or less.
 18. The golf ball of claim 11, wherein the thickness of the first intermediate core layer is greater than the thickness of the second thermoplastic intermediate layer and the thickness of the third thermoplastic intermediate layer.
 19. The golf ball of claim 18, wherein the thickness of the first thermoplastic intermediate layer is from 0.035 inches to 0.075 inches, the thickness of the second thermoplastic intermediate layer is from 0.025 inches to 0.040 inches, and the thickness of the second thermoplastic intermediate layer is from 0.025 inches to 0.040 inches.
 20. The golf ball of claim 11, wherein the surface hardness of the third thermoplastic intermediate layer is greater than the surface hardness of the second thermoplastic intermediate layer, and wherein the surface hardness of the second thermoplastic intermediate layer is greater than the surface hardness of the first thermoplastic intermediate layer. 